Title: RE: [Repeater-Builder] Re: Double the gain or double the power?
Aaron,
The others are correct - you should not have had to add a T to connect the two sections together - they should have been constructed in a way that the two halves of the harness connect together without any
Try a little process of elimination, dummy load the TX before the duplexer and test your output, then re-insert the duplexer and dummy load out of that and compare again, like other people have suggested duplexers on 2m can have high insertion losses, have you checked the patch leads feeding
Jeff I was going to say the same thing. Sounds like he is mounting two, lets say for conversation sake, say DB-222's on top of each other to make a DB-224. Sounds like he is still using the 222 harness' with a T inline. That being said we have an impedance mismatch. The only way to do that
[EMAIL PROTECTED], who eschews obfuscation, said:
Subject: Re: Double the gain or double the power?
Alright for all those that think I'm an idiot, it's true I am!
I went back up to the repeater site and did some testing. I did find
that there was some water in the coax. I blew it out
One thing is being overlooked.
Assuming that this is actually a dual-feed antenna,
the pigtail for the top antenna will be longer than that of the bottom antenna.
This will present an unequal feed to the two halves when using a power divider
and needs to be taken into consideration. One
Yes, I was using the Top Half of a 4-element antenna. I have now
added the 3-Way connector and now have the entire antenna connected.
I have noticed it has cleaned up the receive on week stations but, it
seems to have dropped a little in the signal.
System was just re-tuned, duplexers and
Yes, I was using the Top Half of a 4-element antenna. I have
now added the 3-Way connector and now have the entire antenna
connected.
I have noticed it has cleaned up the receive on week stations
but, it seems to have dropped a little in the signal.
System was just re-tuned, duplexers
The power should not have changed.I suspect you incur an antenna problem when u add the second half, causing some reflected power causing the repeater to start shutting back. Wonder what the forward and reflected power are, before and after?
I am not sure about a 3 way connectorA DB
Yes I have to add a tee for the bottom half. The entire antenna is
one complete unit 4-folded dipoles. Maybe I assumed and thought all
the phasing harness's were already there as I can see where the splits
are on the coax.
It is a VHF system.
I am measuring from out of the duplexers up the
Yes I have to add a tee for the bottom half. The entire
antenna is one complete unit 4-folded dipoles. Maybe I
assumed and thought all the phasing harness's were already
there as I can see where the splits are on the coax.
What kind of antenna is it?
I am measuring from out of the
Commercial antenna *unknown, with 80' LMR-400
I have another set of antenna's (Just 2 folded dipoles) and I can
change it out to see if that makes a difference. Strange, I did try
it with a full wave ringo-ranger and I still lose about 20 watts
through the duplexers.
Aaron
--- In
First check the VSWR. (it may be going up when you
add the second set of elements, the harness must be
done correctly for the VSWR to stay low)
If the VSWR is OK or things are corrected so it seems
OK then retune the duplexer using a Spectrum Analyzer
and Return Loss Bridge. Do this with the
I can't measure the reflected power. I can measure SWR and that is flat.
I am going to change it to another pair of folded dipoles and see if
it changes anything.
Aaron
--- In Repeater-Builder@yahoogroups.com, Steve Bosshard (NU5D)
[EMAIL PROTECTED] wrote:
The power should not have
I'd have to reverse items one and two... but they are both
the big ticket and interplay quite a bit.
Antenna gain is the major performance free lunch you can add
to a radio system and probably the best bang for the buck.
cheers,
skipp
#1 Go for Height.
#2 Go for antenna gain (helps
Hi
20w loss through the duplexer is a huge ammount, have you
measured the foward and reverse pwr of your ant, ideally
a good ant should be almost 1 to 1.
Steve
- Original Message -
From: atms169 [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, May 30, 2006 6:45 PM
Yes I have to add a tee for the bottom half.
That's your problem. You need the specific harness for a 4-bay antenna.
It will have the connector you connect to, which will split into two
paths, then further down each one will split again.
Tee connectors will cut the impedance in half. If you
to me this does not make sence ... what power do you get out of the
duplexer with a dummy load on ..
I think you have a problem with the ant. I don't see why you would lose so
much power out of the duplexer when you add the 2nd set of dipoles ..
Rick
On 30 May 2006 at 16:55, atms169
Alright for all those that think I'm an idiot, it's true I am!
I went back up to the repeater site and did some testing. I did find
that there was some water in the coax. I blew it out and re-sealed
the connectors. Now I am back up to 22-25 watts with a 1.1 match on
the 4 antenna's. So I
if you are loosing 3db in the duplexer then thay are out of wack but you said
thay where tuned ..
2 there is STILL a problem in the coax
3 there could be a problem in the ant connectors
check the specks on the duplexer when you got it tuned it should show you
how much loss and again CHECK
atms169 wrote:
Alright for all those that think I'm an idiot, it's true I am!
I went back up to the repeater site and did some testing. I did find
that there was some water in the coax. I blew it out and re-sealed
the connectors. Now I am back up to 22-25 watts with a 1.1 match on
Hi
getting there. If your coax had water in it, really you should replace it.
I take it that without the duplexer you are getting full
power, if so your duplexer is probably in need of tuning
as it sounds like it is actualy tuned to drop power on the
tx leg and not on the rx.
Steve
- Original
I can't measure the reflected power. I can measure SWR and
that is flat.
You said you had a wattmeter to measure your power output - why can't
you use it to measure the reflected power?
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